Fixes #3858 - Removed the two questionable lines in EventSelection.js
that appeared to have no effect. Researched the whole area of escaping
special characters with the Events palette and discovered that we have a
reasonable general-purpose solution. The exact string entered into an
event field is preserved without modification all of the way into the
model. It is only when we serialize the model (via a getText() call)
that we do the escaping. So, the model might say attribute foo
has value aaa&bbb, and when serialized into HTML content it turns into
foo="aaa&amp;bbb", and when deserialized back into the model it returns
to aaa&bbb. (@peller)